Tempest / BatterySpec AGM batteries?

No experience, but I can offer a clue. The quality of the battery is often proportional to the amount of lead inside. Look at the net weight of the battery for a rough idea. The above kit of two 12V 18A batteries is 12 lbs each. For example, the "plus" version of the same batteries, from the same vendor:

is 13 lbs per battery.

Same from other vendors:

13 lbs

12.6 lbs

12.8 lbs

rest assured that's some no-name chinese battery and quality wasn't a design concern, at all.

Stick with panasonic or yuasa if you care about quality. Some of those are from china now, but are less bogus than the rest of the stuff out there.

A statement full of prejudice and innuendo.

Facts?

It's certainly full of prejudice, but that's our stock in trade around here. If you work in electronics for a couple of decades you build up useful prejudices without explicitly knowing what they are based on. It's unscientific, but science is a tolerably expensive way of building up a body clearly connected facts, while prejudice is cheaper and less reliable, but a great deal better than nothing, particularly when science hasn't got around to quantify what you need to know.

As for innuendo

there's nothing indirect about opinion being presented - its a plain statement of opinion, without any obvious hidden agenda.

-- Bill Sloman, Nijmegen

have fun with your cheapest-found-on-the-internet batteries.